/Engine/Source/Runtime/Core/Public/Templates/SharedPointer.h
Special constructor used internally to cast a 'const' shared pointer a 'mutable' pointer. You should never call this constructor directly. Instead, use the ConstCastSharedPtr() function. This constructor creates a shared pointer as a shared reference to an existing shared pointer after const casting that pointer's object. This constructor is needed for const casts.
template<typename OtherType> TSharedPtr ( [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< OtherType, Mode > const & InSharedPtr, [SharedPointerInternals::FConstCastTag](API\Runtime\Core\Templates\FConstCastTag) )